Efforts to produce an injection moldable, glass fiber reinforced poly(ethylene terephthalate) (PET) which can be molded using molds heated to temperatures less than the polymer's crystallization temperature from the glassy state have been difficult because of the polyester's slow crystallization rate. Combinations of specific nucleating agents with certain types of plasticizers enhance the crystallization kinetics of glass fiber reinforced PET (GFR-PET) to allow one to mold the composition in molds heated to temperatures to less than 110.degree. C. Most of these plasticizers are monomeric, low molecular weight esters prepared by reacting a low molecular weight alcohol with an organic acid. However, many of these low molecular weight organic compounds are somewhat volatile at molding temperatures and tend to vaporize and redeposit on the mold surfaces.
It is the purpose of this invention to provide reinforced polyethylene terephthalate molding blends that can be molded into articles having a smooth, glossy surface, and which do not leave mold deposits and/or are not volatile during molding operations.
Copending application Ser. No. 158,821 filed on 02/22/88, relates to reinforced poly(1,4-cyclohexylene dimethylene terephthalate) containing a primary, linear polymeric alcohol as a crystallization aid.
The following U.S. patents are of interest: U.S. Pat. Nos. 3,435,093, 4,352,904, 4,486,564, 4,223,125 and 4,223,113. While these patents reveal the use of salts of a selected organic polymer containing pendant carboxyl groups in combination with low molecular weight esters, ketones, sulfoxides, nitriles or amides, none suggest the use of a primary, linear polymeric alcohol as described herein as an additive that could be used to enhance the crystallization rate of GFR-PET to result in improved surface smoothness of molded objects.